evaluate vs mull over

evaluate

verb
  • To draw conclusions from examining; to assess. 

  • To compute or determine the value of (an expression). 

  • To return or have a specific value. 

mull over

verb
  • To think deeply about something; to ponder, deliberate or ruminate. 

How often have the words evaluate and mull over occurred in a corpus of books? (source: Google Ngram Viewer )